Window glass antenna

ABSTRACT

A window glass antenna having separate antenna elements for AM and FM radio reception. The antenna elements are connected to a radio receiver through a selector switch, permitting either the FM or AM antenna to be coupled to the radio receiver.

United States Patent Egarashi 1 Apr. 17, 1973 1 WINDOW GLASS ANTENNA [56] References Cited [75] Inventor: Tsuyoshi lgarashi, Chiyoda-ku, UNITED STATES PATENTS Tokyo, Japan 3,484,584 12/1969 Shaw ..343/7ll [73] Assignee: Asahi Glass Company, Tokyo, Japan 2,654,030 9/1953 Cuuilliez .....343/858 3,261,019 7/1966 Lundy ..343/876 [22] 1970 3,576,576 4 1971 Jensen ..343/712 [21] Appl. No.: 94,325 2,838,755 6/1958 Albright et a1. ..343/876 Primary Examiner-Eli Lieberman [30] Foreign Application Priority Data Attorney oblon, Fisher & Spivak Dec. 9, 1969 Japan ..44 1 16410 [57] ABSTRACT [52] US. Cl ..343/7l3, 343/876 51 1111.01. ..H0lq 1/32 A glass antenna havmg Separate antenna [581 Field of Search ..343/712 713 873 mm AM and FM radio receptiml- The antenna 3 elements are connected to a radio receiver through a selector switch, permitting either the PM or AM antenna to be coupled to the radio receiver.

4 Claims, 3 Drawing Figures f l 5 1 1 I3 I 1 I I I I6 '1: 1 l4 PATENTEDAPRIYW 3,728,732

FIG. I

l3 H: T 15 INVENTOR Tsuvosm IEJARASHI WINDOW GLASS ANTENNA BACKGROUND OF THE INVENTION 1 Field Of The Invention This invention relates to a window glass antenna, and more particularly to an antenna to be mounted within a window of a motor vehicle.

2. Description Of The Prior Art It is known that a radio antenna may be mounted on or between the two laminated glass sheets of conventional automobile windows. However, in the past, it has been difficult to provide good sensitivity for receiving both frequency modulated (FM) and amplitude modulated (AM) radio waves with a single dual-purpose antenna, of the type known in the prior art. It has been found, that while such dual-purpose antennas are adequate to receive most AM broadcasts, they provide very poor reception for higher frequency FM signals.

SUMMARY OF THE INVENTION Accordingly, it is one object of this invention to provide a novel window glass antenna for automobiles which provides good sensitivity for both AM and FM radio broadcasts.

This and other objects have been achieved by providing separate antenna elements for FM and AM signals, on or between the laminated glass sheets used for automobile windows. A switch is provided to permit selective use of one or the other of the antenna elements depending upon whether AM or FM broadcasts,

are to be received.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 3 is a plan view of another embodiment of the invention illustrating an automobile window including an antenna configuration different from that of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the Drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views, and more particularly to FIG. I thereof, an automobile window 1 is illustrated. The window I includes an FM radio antenna 2 and an AM radio antenna 3, illustrated in schematic form.

Referring now to FIG. 2, the antenna of the instant invention is shown in greater detail. More particularly, an automobile windshield 11, which may be comprised of two laminated glass sheets with an interposed layer of thermoplastic material, is shown as including an AM antenna 12 as well as an FM antenna 13.

The antennas l2 and 13 may consist either of thin copper wires or printed strips of conductive material,

preferably transparent in nature. If copper wires are to be used, their diameters may be within the range of 0.1 mm. to 1 mm. although wires of diameters between 0.125 and 0.7 mm. have been found most satisfactory. The wire may be inserted in the layer of thermoplastic material which is bonded between the two sheets of window glass as they are laminated together.

If printed conductive strip material is to be used in forming antennas 12 and 13, it has been found that a strip'width of from 0.1 to 2 mm. is ideal. Such strips may be formed of commercial silver paste, the nonvolatile component of which may have approximately the following composition:

Ag 90% PbO 7.3% 8,0, 1.2% sio 0.7% mp 0.7%

This paste may be printed on the window glass using conventional screen printing techniques. In the printing process, the printed glass sheet is heated to about 100C. for 5 minutes to dry the paste. Then, the sheet of printed glass is heat treated in a furnace at approximately 700C. for about 4 minutes to fix the silver paste.

The antenna can also be printed on glass sheet using a conductive solder composed by weight of 40 to 98% Pb, 1.8 to Sn, 0.05 to 10% Zn, and 0.05 to 10% Sb.

Both the shapes of the antennas 12 and 13 and their positioning within windshield ll influence their performance.

More particularly, in positioning the antennas within the window glass of a vehicle, the capacitive effect between the antenna and the metal body of the vehicle must be considered. For example, as the antennas are moved closer to the metal vehicle body, their capacitance increases. Accordingly, it is desirable to position the antenna as far as possible from the automobile body to minimize the capacitive effect. However, it is also important not to obscure the view through the window in which the antenna is mounted. Accordingly, it has been found that in order to minimize the capacitive effect and the vision obscuring effect of the antennas l2 and 13, the main branches of the antennas should be positioned at distances of between 2 to 10 centimeters from the edges of windshield 11.. In addition, in order to minimize the radio interference and spurious noise caused by windshield wipers, as well as to make a good appearance, it is desirable to position the main arms of antennas l2 and 13 as close as possible to the edges of windshield 11 within the 2 centimeter limit above and to run the vertical portion of the antennas directly up the center of windshield l 1.

Both AM and FM antennas l2 and 13 may assume various shapes. As illustrated in FIG. 2, AM antenna 12 may have two principal arm portions extending parallel to the upper edge of windshield l l and two leg portions extending vertically down the center of windshield 11. All portions of the antenna are, of course, interconnected to'form acontinuous conductive line. Similarly, FM antenna 13 may consist of two principal arm portions extending primarily along the bottom edge of windshield 11, with wing portions thereof bent upwardly, following the edge contour of windshield 1 l.

The PM antenna 13 is in general shorter than the AM antenna 12, and it is sometimes preferable that the FM antenna 13 be oriented at least in part in a vertical direction. The AM antenna 12, on the other hand, is preferably relatively long in length and need not be oriented in a vertical direction.

Referring now to FIG. 3, an antenna configuration illustrating these relationships more clearly is shown. More particularly, an AM antenna 12 is shown with its principal arm portions extending along the base of a windshield 11. The antenna 12 includes wing portions at the ends of each of the arm portions thereof, which are bent upwardly in a vertical direction, following the edge contours of windshield 11. An FM antenna 13 is also shown formed of a generally U-shaped conductor or conductive strip consisting primarily of two arm portions-extending vertically up the center of windshield 11.

Of course, it will be understood that both AM and FM antennas may assume numerous other shapes. For example, F M antenna 13 may consist of a short vertical conductive line having many horizontal branch lines extending therefrom. AM antenna 12 may be in the form of a spiral line, a net shape (a plurality of intersecting perpendicular lines), or a base conductive line having many branch lines extending therefrom.

It is also possible for a TV antenna to be imprinted on window glass with a configuration similar to the FM antenna configurations described above.

AM antenna 12 and FM antenna 13 may be coupled to a car radio receiver 14 through lead wires 17 and 16, respectively. Lead wires 16 and 17 may be ordinary shielded cables, as is well known to those skilled in the art (see, for example 0.8. Pat. to Koschmieder, No. 2,213,282, issued Sept. 3, 1940). Selective use of either AM antenna 12 or FM antenna 13 is made possible by the use of a selector switch 15. Selector switch may be interconnected with radio receiver 14 such that whenever the radio receiver is switched to receive FM broadcasts, FM antenna 13 is automatically interconnected and, whenever receiver 14 is switched to receive AM broadcasts, AM antenna 12 is utilized. It is also possible to permanently interconnect AM antenna 12 and FM antenna 13 at a convenient position on windshield 11 such that only a single lead wire is necessary to couple the interconnected antennas to radio receiver 14. If this is done, the AM and FM antennas still function separately, since each antenna is designed to be more sensitive in the frequency range in which it is intended to operate. In this case, the need for selector switch 15 is eliminated.

It will be understood, of course, that while a windshield has been referred to in the description hereinabove, it is also equally possible to install antennas 12 and 13 in the rear or side windows of an automobile. It is also within the scope of the teachings of the instant invention to use an antenna of the type described either in or on the windows of a house or of a building.

In addition, while it is most preferable to use a transparent conductor material for the antenna, it is possible to use fine, opaque wires advantageously. That is, fine wires may be set into the windshield of an automobile, for example, in a pattern that may also be used for sighting the road in front of the automobile.

Obviously, numerous additional modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended Claims, the invention may be practiced otherwise than as specifically described herein.

What is claimed as new and desired to be secured By Letters Patent of the United States is: I 1. A window glass antenna particularly suitable for use with automotive vehicles comprising:

a first antenna element designed to receive only FM radio broadcasts,

a second antenna element separate from said first antenna element and designed to receive only AM radio broadcasts,

said first and second antenna elements formed into different respective shapes and placed on a glass sheet adapted to be mounted to an automotive vehicle body,

said first and second antenna elements positioned on said glass sheet so as to minimize the capacitive effect of said automotive vehicle body on said antenna elements,

one of said first and second antenna elements including a pair of symmetrical arms which extend substantially parallel to a lower edge of said glass sheet,-each of said symmetrical arms including an upturned end portion; and

the other of said first and second antenna elements positioned substantially at the center of said glass sheet and extending from said lower edge thereof toward an upper edge thereof terminating in a pair of symmetrical arms which extend substantially parallel to said upper edge.

2. A window glass antenna as in claim 1, further comprising:

means coupled to said first and second antenna elements for connecting said elements to a radio receiver, said means including a first lead wire coupled to said first antenna element,

a second lead wire coupled to said second antenna element, and,

a selector switch coupled to said first and second lead wires for selectively interconnecting said first or second antenna element to said radio receiver.

3. A window glass antenna as in claim 1, in which said first and second antenna elements are comprised of printed conductive lines consisting of an electroconductive composition including a metal and a metal oxide.

4. A window glass antenna as in claim 1, in which said antenna elements are comprised of a conductive line consisting of an electroconductive solder.

I! l' l i t 

1. A window glass antenna particularly suitable for use with automotive vehicles comprising: a first antenna element designed to receive only FM radio broadcasts, a second antenna element separate from said first antenna element and designed to receive only AM radio broadcasts, said first and second antenna elements formed into different respective shapes and placed on a glass sheet adapted to be mounted to an automotive vehicle body, said first and second antenna elements positioned on said glass sheet so as to minimize the capacitive effect of said automotive vehicle body on said antenna elements, one of said first and second antenna elements including a pair of symmetrical arms which extend substantially parallel to a lower edge of said glass sheet, each of said symmetrical arms including an upturned end portion; and the other of said first and second antenna elements positioned substantially at the center of said glass sheet and extending from said lower edge thereof toward an upper edge thereof terminating in a pair of symmetrical arms which extend substantially parallel to said upper edge.
 2. A window glass antenna as in claim 1, further comprising: means coupled to said first and second antenna elements for connecting said elements to a radio receiver, said means including a first lead wire coupled to said first antenna element, a second lead wire coupled to said second antenna element, and, a selector switch coupled to said first and second lead wires for selectively interconnecting said first or second antenna element to said radio receiver.
 3. A window glass antenna as in claim 1, in which said first and second antenna elements are comprised of printed conductive lines consisting of an electroconductive composition including a metal and a metal oxide.
 4. A window glass antenna as in claim 1, in which said antenna elements are comprised of a conductive line consisting of an electroconductive solder. 